This invention relates to conduit fittings or bodies as used in electrical wiring systems, and more specifically to construction of the access cover plate for the body. The cover may be provided with seals to limit entry of moisture into the conduit.
Conduit bodies are employed in electrical wiring systems in which electrical conductors are routed through rigid conduit. They normally incorporate two or more cylindrical portions with internal threads, into which the threaded ends of the rigid conduit are assembled. A removable cover plate allows access to the interior of the body, and permits pulling a group of conductors through the conduit, or making electrical connections as required. Some bodies incorporate internal threaded portions at right angles to one another to permit the conductors to make a right angle turn. Some styles have a side outlet that permits one or more of the conductors to leave the basic bundle and be routed into their own conduit as required. Although the detailed design of the body may vary from manufacturer to manufacturer, there is sufficient standarization to permit units from different manufacturers to be interchanged.
The prior art includes various structures for securing the cover plate to the body proper. In some cases the cover is merely secured to the body by screws passing through the flange area of the cover and threading into a suitable hole in the body. Assembly is easily accomplished, but the screws are loose pieces and can be easily lost. If the cover plate is to be removed and reinstalled a number of times, the hole in the body into which the screw assembles can rust and break off on occasion which causes a difficult drilling and tapping problem. In the drawings that accompany this specification, FIG. 6 illustrates an example of a typical prior art construction. In this design the screw is captured and becomes a part of the the cover, but the detail parts involved--a formed sheet metal detail, a sleeve which is riveted in place, and a formed dog with a threaded hole--appear to be unnecessarily complex and costly. This and similar prior art constructions basically employ an inclined ramp or plane that forces the dog outward beyond the axial extremity of the elongated cover as the screw is tightened.
It is a primary object of the invention to provide apparatus which has a minimum number of parts and which is easy to manufacture and assemble.
It is an object of this invention to provide a cover plate assembly capable of being assembled and disassembled repeatedly without deterioration of the ability of the cover to seal.
It is a further object of this invention to provide a cover plate system in which the attaching screws are captured and not loose pieces.
A still further object is a cover plate that is easily assembled and removed without any special tools.
Another object of the invention is to provide a conduit body that is interchangeable with other bodies that are currently available.
Other objects and advantages of the present invention will readily occur to one skilled in the art to which the invention pertains upon reference to the following detailed description.